In the process of manufacturing certain precision apparatus such as an array of ink jet charge electrodes for example, it is desirable to use a single material which is capable of being converted in multiple coexisting phases where these phases have significantly different chemical behavior. One example is the use of photosensitive glass which can be caused to change characteristics when exposed to suitable radiation, giving rise to differential etching properties.
However, conventional techniques are not sufficient to produce items such as an array of ink jet charge electrodes due to the precision size and small spacing required. The taper resulting from a conventional etching process would make the densely packed array of charge electrodes impossible to achieve.
It is therefore the major object of the present invention to provide a process whereby precision apparatus such as an array of ink jet charge electrodes can be made from materials such as photosensitive glass by a novel etching process.